Among all the therapies that are called ‘complementary’, phytotherapy is the one that can draw on the most scientific support. This book is constructed largely on the foundation of published literature. It is clear that there is now a sufficient case to construct a rational therapeutic system from the older traditions. However, in spite of this and the presence in medicinal plants of many pharmacologically active constituents, the most persistent doubt expressed by the medical world is whether whole herbs actually work in practice.

Most published material on phytomedicines is based on laboratory research rather than on observed effects in humans of realistic doses. There is still a relative paucity of top-quality controlled clinical studies of the whole herb. Moreover many good clinical studies show only a modest effect beyond placebo. Critics also point out that pharmacological constituents in most herbs are at relatively low levels in a final therapeutic dose, that the complexity of constituents is at least as likely to reduce as to potentiate activities, and that traditional reputation is often clouded by plagiarism and inappropriate transmission.

On the other hand, most herbal practitioners will attest to consistent therapeutic performance and will also have accounts of dramatic responses from their patients, where genuinely powerful pharmacological effects have followed consumption of herbal prescriptions, often after conventional treatments had failed. They will also point to the essential features of clinical trial data as denying precisely that which they value most about their therapy – the individualisation of treatment and response. As an example, experimental data consistently deny the possibility of appreciable diuretics among plant remedies, yet substantial diuresis in individual patients is one of the most familiar treatment reactions in practice. Such experiences are enough to convince most practitioners that herbal medicine is a serious alternative to conventional drug treatment with few of the adverse effects.

Any move in the stand-off between the sceptics and the believers is, however, likely to include a full discussion of the placebo effect.

Honesty can be painful to all health practitioners: it is likely that most benefits seen in taking any therapy are not produced directly by the treatments themselves. This is the main conclusion reached after taking into account the substantial literature about placebo.

The term ‘placebo effect’ itself is not wholly appropriate for this discussion. It derived originally from observations in double blind clinical studies where the treatment was compared with a dummy pill made to look as close as possible to the treatment, with neither the patient nor the practitioner aware of which was which. Early observations were that a significant proportion of subjects in such studies who were taking the dummy nevertheless got better. Initial impressions in the 1940s and 1950s, when such rigorous studies became more common, were that figures varied from trial to trial, but it appeared that about a third of subjects were likely to be ‘placebo responders’. This behaviour was put down, in the psychosomatic model emerging at the same time, as reflecting a particular suggestibility on the part of that proportion of the population. As a result the placebo response has been seen to be a non-serious event, not something to be confused with real medicine and at worst a confounding nuisance in establishing therapeutic efficacy for treatments.

Many doctors and other practitioners became used to thinking that about a third of their patients would get better whatever they were given and many thought they knew who they were! After discounting this element they were pleased to feel that any further improvement in their patient population was a result of therapeutic efficacy and skill. Herbal practitioners have therefore been able to confirm to themselves that there must be much more to account for the evidence before their eyes.

Both practitioners and sceptics must review their opinion about the placebo effect in the light of overwhelming later evidence. The last 50 years have completely overturned early prejudices. In brief, it is now possible, after analysis of the clinical trial literature, to confirm that:

The first real shock to the herbal practitioner is that those ‘conditions and circumstances’ where placebo responses have been recorded as particularly high include many of those covered by herbal and other complementary treatments. There is support for the cynic’s case that the success of herbal tradition over centuries, especially that drawn from close-knit early societies (where placebo responses were likely to be particularly high because of stronger peer pressures and belief systems), could be due to benefits other than the treatment itself.

The shock also applies, however, to conventional medicine and especially surgery, where placebo responses, as evidenced by examining data from non-controlled clinical studies of surgical interventions which were later found to be valueless, are among the highest recorded.² The simple instruction from a doctor carries enormous ‘placebo’ impact.¹² In whole industries, such as those promoting antidepressant drugs, the impact of placebo relative to treatment response has probably been systematically understated.¹³

Among both conventional and complementary healthcare practitioners there is an understandable feeling that cures having nothing to do with the treatment so skilfully provided are something of an embarrassment and even a challenge to one’s choice of vocation. Thus the placebo effect is one of the least discussed phenomena in clinical medicine. Yet it is by far the most powerful factor of all.

The way through this potential difficulty is to reconsider what the placebo response means.

When a moderate cut is sustained, one assumes it will heal itself. A cold or bout of influenza will generally get better on its own. The only treatment for serious trauma like broken bones or operation wounds is to put the tissues back together and leave them for natural healing to occur.

No one doubts that self-repair is a vital phenomenon. Nevertheless, medicine has moved away from the classic principle that all healing is self-healing, that the vis medicatrix naturae, the healing power of life, is the only healer and that the physician should do no more than help it on its way. Exasperation at the slow and uncertain pace of natural healing, the realisation that one can save lives and health by stepping in with something direct and powerful, has led to the discovery of healing bullets. The modern success in this venture has allowed medicine to forget the fundamental principle that ultimately no drug or surgery actually heals: its value is in reducing pain and distress, returning an acceptable function and at best enabling spontaneous repair to occur when it had previously been prevented.

There is no problem with the modern strategy in many clinical cases; it is certain that it can save lives and protect health in ways inconceivable to prescientific medicine. Nevertheless, there is another strategy that may be more appropriate in many other clinical conditions, a therapeutic approach with the primary objective of supporting self-repair. This could be most appropriate in facing the challenge of chronic diseases, the broad range of indeterminate syndromes, along with the numerous minor self-limiting symptoms that make up the vast majority of the family practitioner’s caseload.

What researchers have labelled as the placebo effect in their clinical trials may be described as an improvement in self-repair. That it was merely the effect of being recruited into the clinical study and being given a dummy treatment (the main feature of most clinical trials is the increased attention that subjects receive for their condition) is surely evidence of how little it can take to mobilise this self-repair. Dismissing placebo healing as just suggestibility is to miss the point; as shown above, placebo healing can occur in any subject when the circumstances are right.

Indeed, some medical practitioners have got the point. There is a long unspoken tradition of non-specific prescribing, with vitamins, laxatives, aspirin and, unfortunately, antibiotics to keep the patient happy (placebo means ‘I please’), although actual prescription of placebos as such usually breaches ethical and legislative codes.

Many researchers prefer to use the term ‘non-specific effects’ to describe contributions to improvements in clinical studies that are not caused by the treatment in isolation. As well as the placebo effect itself, they include the natural course of the illness (‘getting better anyway’ is something ‘control groups’ of non-treated patients are supposed to quantify in the better organised clinical trials but even here confusion reigns about hidden ‘placebo effects’¹⁴), ‘spontaneous remission’ (generally used to describe recovery that cannot otherwise be explained), a trend for improvement (‘regression to the mean’) due to the fact that people tend to get recruited to studies (and come to obtain treatment) when they are at their worst. All these phenomena are aspects of self-repair. A shift in terminology so that the generally prejudicial ‘placebo effect’ becomes ‘non-specific effects’ will be welcome.

In reflecting on practice experience with the full impact of the placebo literature in mind, one could easily become dismayed at the difficulty in separating possible herbal treatment effects from non-specific effects. Nevertheless, one is quickly reminded of the peculiar properties of herbal remedies; time and again one sees in practice changes that are characteristic of the remedies, rather than fitting any preconceived notion of a placebo response. Changes in physiological functions, in digestion, bowel performance, expectoration, diuresis, circulation and many others can often be invoked. There is enough evidence to support the view that many herbal remedies have appreciable effects on various organ and tissue functions, much of which is considered throughout this book.

If this is the case and the objectives of treatment are to better mobilise self-repair functions, then herbal remedies could have unique prospects for this job. If non-specific responses are manifestations of such mobilisation then, to put it simply, the role of the herbal practitioner is to improve such responses. No one needs to feel their vocation is challenged if they acknowledge the large contribution of non-specific factors in their professional performance. It may even be possible to develop research questions that test the hypothesis that herbal remedies have unique prospects for mobilising the self-repair functions.

Whatever the argument for or against the benefits of herbal medicine, this has been driven more by prejudice on both sides than by the evidence. It is time to review the status of research so far and pose new, more appropriate methods for the future.

Judging by the substantial markets for herbal products in the developed world, let alone the vast use in traditional cultures, a great many people have already found herbal medicines useful. Compared with the experience of most modern drugs, the human use and approval of most herbal remedies is phenomenal. The requirement by the medical and scientific establishment for research to ‘prove’ that herbs are effective is not found among the population at large. It is apparent that most ordinary people are content to rely on their impressions of the world to get by in it.

Knowledge within traditional medicine has also generally been in the form of received wisdom moulded to the individual needs and prowess of each practitioner. Such means of acquiring healing skills seem temperamentally suited to most practitioners, herbal and conventional, even today. Their interest in inquiry for its own sake, with secure truths up for constant possible refutation, is understandably secondary to their concern to survive in practice. In the case of herbal medicine, adherents understandably tend to give it the benefit of doubt. The view that: ‘What worked for our grandparents is good enough for me, and at least it is natural’ probably generates a casual approach about research. It is also possible to question the validity of the research forum and only to play it as far as absolutely necessary (so that the rights to supply herbs are not restricted by law).

Moreover, in spite of the public indifference to the evidence base, they do want to be assured that someone is looking after them. They therefore assume the questions are being asked by those who ought to do it. The physician and the regulators are charged with the job of making sure that medicine is safe and effective. There are internal reasons why some practitioners may be willing to submit to the rigours of the research method: a simple pride in the therapy might generate the challenge ‘If what you say is so valuable and powerful then it should be able to stand up for itself in any forum’.

There are, however, practical problems in pursuing good clinical research in herbal medicine:

Even with these difficulties, conventional double blind randomised clinical trials can sometimes be completed, although the track record so far is patchy. The controlled trial is a notably flexible instrument and clinical trial data at least involve rigorous observations of human use of plants: of the forms of research available they are by far the most valuable in making clinical judgments. For now there are many hundreds of well-conducted random-assigned, double blind controlled studies, and even systematic reviews of these, at least for the proprietary products on the market. The monographs in this text also include well-conducted clinical trials for products based on valerian, feverfew, ginger, saw palmetto and others. These studies show that the conventional methodology is very powerful and can be suited to understanding herbal remedies in some contexts at least. They also show that even such unremarkable plants, when researched thoroughly, can demonstrate efficacy beyond the placebo.

It is also important to counter some practitioner resistance to clinical trials. Some have decried them as inherently unethical, in denying a proportion of patients the most useful treatment. However, the researcher goes into a controlled clinical study professionally neutral to the outcome: the point is that until the study is complete there is no ‘most useful treatment’. Second, no study in a developed country could proceed without painstaking adherence to the principle of informed consent and to other reassurances that the interests of the subject are paramount. The ethics committees that legally review all orthodox study protocols are charged to represent the interests of the subjects (and this includes rejecting studies that are not sufficiently well designed to actually answer the question). Indeed, medical researchers may point out in their terms that administering a remedy that has not been proven by good-quality research is itself unethical. This may not be an argument for herbal practitioners to pursue too far!

Moreover it should be recognised that OTC herbal use far outstrips practitioner prescription, probably by a factor of more than 20:1 even in Europe.¹⁹ For researching OTC label indications for single medicinal products, in which individual responses to remedies are not the critical issue, the double blind controlled clinical trial is clearly the most applicable method. In addition, as the ‘patient’ is in many cases not being diagnosed professionally and is determining his or her own treatment and prognosis, self-assessment questionnaires are often an appropriate measure of progress. These are not expensive to administer. This is often ‘out-patient’ medicine. Research costs can be saved as close clinical supervision need not be always be necessary throughout the trial.

Unfortunately clinical research on herbs has often also been of indifferent methodological quality. Modern studies, even those otherwise highly rated, can be undermined because they neglect basic precautions against the very variable quality of herbal products. In a surprising proportion of clinical trial papers the herbal product used is not quantified, stabilised or verified.²⁰ Other studies may not relate to the herbal remedy as such but to its chemically-defined ingredients.

Perhaps future hopes for a new injection of investment in clinical research lie with the moves towards sustainable economic development in countries around the world. Renewed interest in the potential of indigenous medical traditions, in some cases linked to emerging economies, has increased research activities in a wider range of plants.²¹ At best, standards developed for herbal research in Europe can be exported to improve the quality of investigation elsewhere and to new products linked to sustainable ‘free trade’ arrangements. There is still a hunger for beneficial natural medicines. If there is any substance in the promise, new ways will be found to service that demand. This phenomenon has already begun, as evidenced by the clinical data being generated in India and China, of which this book contains many examples.

So the practical applications of the conventional controlled clinical trial to herbal practice are mixed. It would be helpful to develop other techniques to explore how herbs affect human beings. There have fortunately been some considerable efforts in constructing appropriate methodologies of sufficient weight.²² These include looking at different outcome measures, applying rigorous observational studies and monitoring individual case studies.